code: def on_iteration_start(self, logs=None):
      for cb in self.callbacks:
          cb.on_iteration_start(logs)
  
file_path: mljar-supervised/supervised/callbacks/callback_list.py
label_desc: Use image node_id 5 for calling the CallbackList obj's underlying member method code with example usage: obj.on_iteration_start(logs) without return types